note 58488 added to language.oop5.autoload

While __autoloading is a nice feature, one can stumble upon small problem with it. Imagine: file A.php: <? function __autoload($cname) { require_once "include/$cname.php";} } B::testC(); ?> file B.php: <? function __autoload($cname) { require_once "include/$cname.php";} } class B { public static function test() { C::testMe(); } } ?> file C.php: <? class C { public static function testMe() { print("OK!"); } } ?> Now, running file A.php will result in an error.. because from A's point of view, function __autoload is declared twice - once in A.php, and in required_once'd B.php, too! [Not mentioning that C.php and many many many other required or included files could use it too :) ] So, of course we can remove the duplicate __autoload functions from B.php and any other required files. Thus, we either disallow usage of B.php independently (and other required-able/include-able files!) , as without the __autoload it can not work -- or we have to manually require_once its dependecies, thus making manually the job of __autoload. Irritating, isn't it? A simple trick can help us here. Every file you would place an __autoload function, place instead something like: if(!function_exists("__autoload")) { //your __autoload declaration, for example: function __autoload($cname) { require_once "include/$cname.php"; } } When I first tried it, I was really surprised that you can control functions' declaration with simple IF, without any evals or other tricks. Well.. it's probably a basic "trick", but I didn't notice it anywhere. Feel free to remove it if it was already posted somewhere:) ---- Manual Page -- http://www.php.net/manual/en/language.oop5.autoload.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+58488 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+58488&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+58488&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+58488&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+58488&report=yes&reason=useless Delete: non-english -- http://master.php.net/manage/user-notes.php?action=delete+58488&report=yes&reason=non-english Delete: already in docs -- http://master.php.net/manage/user-notes.php?action=delete+58488&report=yes&reason=already+in+docs Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+58488&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+58488&report=yes Search -- http://master.php.net/manage/user-notes.php